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Pulmonary Embolism

Topic Overview

What is pulmonary embolism?

Pulmonary embolism is
the sudden blockage of a major blood vessel (artery) in the lung, usually by a
blood clot. In most cases, the clots are small and are not deadly, but they
can damage the lung. But if the clot is large and stops blood flow to the lung,
it can be deadly. Quick treatment could save your life or reduce the risk of
future problems.

What are the symptoms?

The most common symptoms
are:

Sudden shortness of breath.

Sharp chest pain that is worse when you cough or take a deep
breath.

A cough that brings up pink, foamy mucus.

Pulmonary embolism can also cause more general symptoms.
For example, you may feel anxious or on edge, sweat a lot, feel lightheaded or
faint, or have a fast heart rate or
palpitations.

If you have symptoms like
these, you need to see a doctor right away, especially if they are sudden and
severe.

What causes pulmonary embolism?

In most cases,
pulmonary embolism is caused by a blood clot in the leg that breaks loose and
travels to the lungs. A blood clot in a vein close to the skin is not likely to
cause problems. But having blood clots in deep veins (deep vein thrombosis) can lead to pulmonary embolism. More than 300,000 people each year have deep vein thrombosis or a pulmonary embolism.footnote 1

Other things
can block an artery, such as tumors, air bubbles,
amniotic fluid, or fat that is released into the blood
vessels when a bone is broken. But these are rare.

What increases your risk of pulmonary embolism?

Anything that makes you more likely to form blood clots increases your
risk of pulmonary embolism. Some people are born with blood that clots too
quickly. Other things that can increase your risk include:

Being inactive for long periods. This can
happen when you have to stay in bed after surgery or a serious illness, or when
you sit for a long time on a flight or car trip.

Recent surgery
that involved the legs, hips, belly, or brain.

Some diseases, such as cancer,
heart failure,
stroke, or a severe infection.

Pregnancy and childbirth (especially if you had a
cesarean section).

Taking birth control
pills or
hormone therapy.

Smoking.

You are also at higher risk for blood clots if you are an
older adult (especially older than 70) or extremely overweight (obese).

How is pulmonary embolism diagnosed?

It may be
hard to diagnose pulmonary embolism, because the symptoms are like those of
many other problems, such as a
heart attack, a
panic attack, or
pneumonia. A doctor will start by doing a physical
exam and asking questions about your past health and your symptoms. This helps
the doctor decide if you are at high risk for pulmonary embolism.

How is it treated?

Doctors usually treat pulmonary
embolism with medicines called
anticoagulants. They are often called blood thinners,
but they don't really thin the blood. They help prevent new clots and keep
existing clots from growing.

Most people take
a blood thinner for a few months. People at high risk for blood clots may need it for
the rest of their lives.

If symptoms are severe and
life-threatening, "clot-busting" drugs called thrombolytics may be used. These
medicines can dissolve clots quickly, but they increase the risk of serious
bleeding. Another option is surgery or a minimally invasive procedure to remove the clot (embolectomy).

Some people can't take blood thinners, or they form clots in spite of
taking the medicine. To prevent future problems, they may have a filter put
into the large vein (vena cava) that carries blood from the lower body to the
heart. A
vena cava filter helps keep blood clots from reaching
the lungs.

If you have had pulmonary embolism once, you are more
likely to have it again. Blood thinners can help reduce your risk, but they
increase your risk of bleeding. If your doctor prescribes blood thinners, be
sure you understand how to take your medicine safely.

You can reduce your risk of pulmonary
embolism by doing things that help prevent blood clots in your legs.

Avoid sitting for long periods. Get up and
walk around every hour or so, or flex your feet often.

Get moving
as soon as you can after surgery.

When you travel, drink extra
fluids. But avoid drinks with alcohol or caffeine.

Wear
compression stockings if you are at high risk.

If you take blood
thinners, take them just the way your doctor tells you to.

Cause

Pulmonary embolism is caused by a blocked artery in the lungs. The most common
cause of such a blockage is a blood clot that forms in a
deep vein in the leg and travels to the lungs, where
it becomes lodged in a smaller lung artery.

Almost all blood
clots that cause pulmonary embolism are formed in the
deep leg veins. Clots also can form in the deep
veins of the arms or pelvis.

Sometimes blood clots develop in
surface veins. But these clots rarely lead to
pulmonary embolism.

In rare cases, pulmonary embolism may be
caused by other substances, including:

Small masses of infectious
material.

Fat, which can be released into the bloodstream after
some types of bone fractures, surgery, trauma, or severe burns.

Air
bubbles or substances that get into the blood from trauma, surgery, or medical procedures.

Tumors caused by rapidly growing cancer cells.

Symptoms

The symptoms of
pulmonary embolism may include:

Shortness of breath that may occur
suddenly.

Sudden, sharp chest pain that may become worse with deep
breathing or coughing.

Pulmonary embolism may be hard to diagnose because its
symptoms may occur with or are similar to other conditions, such as a
heart attack, asthma, a
panic attack, or
pneumonia. Also, some people with pulmonary embolism
don't have symptoms.

What Happens

If a large blood clot blocks
the artery in the lung, blood flow may be completely stopped, causing sudden
death. A smaller clot reduces the blood flow and may cause damage to lung
tissue. But if the clot dissolves on its own, it may not cause any major
problems.

Symptoms of
pulmonary embolism usually begin suddenly. Reduced
blood flow to one or both lungs can cause shortness of breath and a rapid heart
rate. Inflammation of the tissue covering the lungs and chest wall (pleura) can
cause sharp chest pain.

Doctors will consider aggressive steps when they are
treating a large, life-threatening pulmonary embolism.

Chronic or recurring pulmonary embolism

Blood clots that cause
pulmonary embolism may dissolve on their own. But if you have had pulmonary
embolism, you have an increased risk of a repeat episode if you do not receive
treatment. If pulmonary embolism is diagnosed promptly, treatment with
anticoagulant medicines may prevent new blood clots from forming.

The risk of having
another pulmonary embolism caused by something other than blood clots varies.
Substances that are reabsorbed into the body, such as air, fat, or amniotic
fluid, usually do not increase the risk of having another episode. Cancer
increases the risk of blood clots.

Having multiple episodes of
pulmonary embolism can severely reduce blood flow through the lungs and heart.
Over time, this increases blood pressure in the lungs (pulmonary hypertension),
eventually leading to right-sided
heart failure and possibly
death.

Slowed blood flow

When blood does not circulate
normally, clots are more likely to develop. Reduced circulation may result
from:

Long-term bed rest, such as if you are
confined to bed after an operation, injury, or serious
illness.

Traveling and sitting for a long time, especially when
traveling long distances by airplane.

Leg paralysis. When you use your muscles, the muscles contract,
and that squeezes the blood vessels in and around the muscles. The squeezing
helps the blood move back toward the heart. Paralysis can reduce circulation
because the muscles can't contract.

Abnormal clotting

Some people have blood that
clots too easily or too quickly. People with this problem are more likely to
form larger clots that can break loose and travel to the lungs. Conditions that
may cause increased clotting include:

Inherited factors. Some people have an
inherited tendency to develop blood clots that can lead to pulmonary
embolism.

Family history of close relatives, such as a sibling, who has had deep vein thrombosis or pulmonary embolism.

Exams and Tests

Diagnosing
pulmonary embolism is difficult, because there are many other medical conditions, such as a
heart attack or an
anxiety attack, that can cause similar symptoms.

Diagnosis depends on an
accurate and thorough
medical history and ruling out other conditions. Your
doctor will need to know about your symptoms and
risk factors for pulmonary embolism. This information, combined
with a careful
physical exam, will point to the initial tests that
are best suited to diagnose a
deep vein thrombosis or pulmonary embolism.

Tests that are often done if you have shortness of breath or chest pain
include:

A
chest X-ray. Results may rule out an enlarged heart or
pneumonia as a cause of your symptoms. If the chest
X-ray is normal, you may need further testing.

Electrocardiogram (EKG, ECG). The electrical activity
of the heart is recorded with this test. EKG results will help rule out a
possible heart attack.

A blood test to look at
the level of the protein
troponin. Higher levels of troponin can mean there is
damage to your heart muscle.

Treatment Overview

Treatment of
pulmonary embolism focuses on preventing future
pulmonary embolism by using
anticoagulant medicines. Anticoagulants prevent
existing blood clots from growing larger and help prevent new ones from
developing.

If symptoms are severe and life-threatening,
immediate and sometimes aggressive treatment is needed. Aggressive treatment
may include
thrombolytic medicines, which can dissolve a blood
clot quickly but also increase the risk of severe bleeding. Another option for
life-threatening, large pulmonary embolism is to remove the clot. This is
called an embolectomy. An embolectomy is done during a surgery or minimally invasive procedure.

Some people may also benefit from having a
vena cava filter inserted into the large central vein
of the body. This filter can help prevent blood clots from reaching the lungs.
This filter might be used if you cannot take an anticoagulant. Or it might be used if anticoagulants have not worked well enough to lower your risk for blood clots.

Prevention

The risk of
forming another blood clot is highest in the weeks after the first episode of
pulmonary embolism. This risk decreases over time. But the risk remains high
for months and sometimes years, depending upon what caused the pulmonary
embolism. People with recurrent blood clots and/or pulmonary embolism may have
to take anticoagulants daily for the rest of their lives. Anticoagulant medicines also are often used for people who
are not active due to illness or injury, or people who are having surgery on
the legs, hips, belly, or brain.

Other
preventive methods may also be used, such as:

Getting you moving shortly after
surgery.

Wearing
compression stockings to help prevent leg deep vein
thrombosis if you are at increased risk for this condition.

If you are already at high risk for pulmonary embolism or deep vein thrombosis, talk to your doctor before taking a long flight or car trip. Ask if you need to take any special precautions to prevent blood clots during travel.

Home Treatment

Home treatment is not recommended for
initial treatment for
pulmonary embolism. But it is important for preventing
more clots from developing and causing a
deep vein thrombosis, which can lead to recurring
pulmonary embolism.

Measures that reduce your risk for developing
a deep vein thrombosis include the following:

Exercise. Keep blood moving in your legs by
pointing your toes up toward your head so that your calves are stretched, then
relaxing. Repeat. This exercise is especially important when you are sitting
for long periods of time, for example, on long driving trips or airplane
flights.

Get up out of bed as soon as possible after an illness or
surgery. It is very important to get moving as soon as you are able. If you
cannot get out of bed, do the leg exercises described above every hour to keep
the blood moving through your legs.

Quit smoking.

Wear
compression stockings to help prevent leg deep vein
thrombosis if you are at increased risk for this condition.

Medications

Medicines can help prevent repeated
episodes of
pulmonary embolism by preventing new blood clots from
forming or preventing existing clots from getting larger.

Anticoagulants

Anticoagulants are prescribed when pulmonary embolism
is diagnosed or strongly suspected.

You'll likely take an anticoagulant for at least 3 months after
pulmonary embolism to reduce the risk of having another blood clot.footnote 2 Treatment
with anticoagulants may continue throughout your life if the risk of having
another pulmonary embolism remains high.

Different types of anticoagulants are used to treat pulmonary embolism. Talk with your doctor to decide which medicine is right for you.

In the hospital, you might be given an anticoagulant as a shot or through an IV. After you go home, you might give yourself shots for a few days. For the long term, you'll likely take a pill.

Anticoagulants include:

Apixaban.

Dabigatran.

Heparin.

Rivaroxaban.

Warfarin.

Safety tips for anticoagulants

If you take an anticoagulant, you can take steps to prevent bleeding. This includes preventing injuries and getting regular blood tests if needed.

Thrombolytics

Clot-dissolving (thrombolytic) medicines are not
commonly used to treat pulmonary embolism. Although they can quickly dissolve a
blood clot, thrombolytics also greatly increase the risk of serious bleeding.
They are sometimes used to treat a life-threatening pulmonary
embolism.

Surgery

The removal of a clot is called an
embolectomy. An embolectomy might be done during a surgery. Or it might be done with a minimally invasive procedure that uses a catheter (a thin tube that is guided through a blood vessel). This type of treatment for
pulmonary embolism is used only in rare cases. It is considered
for people who can't have other kinds of treatment or those whose clot is so
dangerous that they can't wait for medicine to work. An embolectomy also may
be an option for a person whose condition is stable but who shows signs of
significant reduced blood flow in the pulmonary artery.

What to think about

Surgery increases the risk of
forming new blood clots that can cause another pulmonary embolism.

Other Treatment

Some people cannot take
anticoagulant medicines, or they continue to develop blood clots despite taking
the medicines. If surgery or medicines are not options, other methods of
preventing
pulmonary embolism may be considered, such as a vena
cava filter.

Other treatment choices

A
vena cava filter may be inserted in the large central
vein that passes through the abdomen and returns blood from the body to the
heart (vena cava). This filter can prevent blood clots in the leg or pelvic
veins from traveling to the lungs and heart. These filters may be permanent or
removable.

What to think about

Vena cava filters aren't
typically recommended as the first treatment for pulmonary embolism. But they may be
considered if you:

You have problems taking anticoagulant medicine.

Your anticoagulant has not worked well enough to lower your risk for blood clots.

Vena cava filters can cause serious health problems if they break or become
blocked with one or more blood clots.

Vena cava filters have not
been shown to lower the death rate in people with pulmonary embolism.footnote 3

Other Places To Get Help

Organizations

American College of Cardiology: CardioSmart

www.cardiosmart.org

American Heart Association (AHA)

www.heart.org

National Heart, Lung, and Blood Institute (NHLBI) (U.S.)

www.nhlbi.nih.gov

Related Information

References

Citations

U.S. Department of Health and Human Services (2008). The Surgeon General's call to action to prevent deep vein thrombosis and pulmonary embolism. Available online: http://www.surgeongeneral.gov/library/calls/deepvein/index.html.

U.S. Department of Health and Human Services (2008). The Surgeon General's call to action to prevent deep vein thrombosis and pulmonary embolism. Available online: http://www.surgeongeneral.gov/library/calls/deepvein/index.html.

U.S. Department of Health and Human Services (2008). The Surgeon General's call to action to prevent deep vein thrombosis and pulmonary embolism. Available online: http://www.surgeongeneral.gov/library/calls/deepvein/index.html.

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